Enhancing Light Extraction of Inorganic Scintillators Using Photonic Crystals

Abstract

Abstract:Inorganic scintillators are commonly used as sensors for ionizing radiation detectors in a variety of applications, ranging from particle and nuclear physics detectors, medical imaging, nuclear installations radiation control, homeland security, well oil logging and a number of industrial non-destructive investigations. For all these applications, the scintillation light produced by the energy deposited in the scintillator allows the determination of the position, the energy and the time of the event. However, the performance of these detectors is often limited by the amount of light collected on the photodetector. A major limitation comes from the fact that inorganic scintillators are generally characterized by a high refractive index, as a consequence of the required high density to provide the necessary stopping power for ionizing radiation. The index mismatch between the crystal and the surrounding medium (air or optical grease) strongly limits the light extraction efficiency because of total internal reflection (TIR), increasing the travel path and the absorption probability through multiple bouncings of the photons in the crystal. Photonic crystals can overcome this problem and produce a controllable index matching between the crystal and the output medium through an interface made of a thin nano-structured layer of optically-transparent high index material. This review presents a summary of the works aiming at improving the light collection efficiency of scintillators using photonic crystals since this idea was introduced 10 years ago.

Inorganic, Organic, and Perovskite Halides with Nanotechnology for High–Light Yield X- and γ-ray Scintillators

“…The concepts and modeling of the enhanced extraction mechanism have been detailed in a review by Knapitsch and Lecoq in 2014 [156]. Further extensive reviews on the works on photonic crystal on scintillators have been done in 2018 by Salomoni et al [157]. In this review we discuss systemically the nanostructuring methods, as well as QD and nanocrystal scintillators as another alternative to improve scintillating performance.…”

Nanosphere Lithography for Structuring Polycrystalline Diamond Films

“…We believe that NLS represents a promising method for ingenious designs, and that exploring new procedures for nano-/micro-structuring diamond will open new fields of diamond applications, such as photonic materials [3,22,29,53], Raman or fluorescence plasmonic structures [12,14,18,38], metasurfaces [37,54], biomimetic surfaces (e.g., moth-eye structure) [24], biological and chemical sensors [13,54,55], surfaces with specific wetting properties (e.g., superhydrophobicity, anti-fogging, self-cleaning) [12,19], and many others.…”

Absolute Luminescence Efficiency of Europium-Doped Calcium Fluoride (CaF2:Eu) Single Crystals under X-ray Excitation

“…The use of single crystals as radiation converters is very common in imaging or counting applications, especially when coupled with optical sensors such as photomultipliers, which are frequently employed in radiation detectors [1,2]. Additionally, they are widely used in particle physics, homeland security, and in numerous disciplines of medical imaging, such as X-ray computed and positron emission tomography (CT and PET, respectively), radiotherapy, radiography, and mammography [3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

“…The state-of-the-art electronics that are used in today's imaging systems require scintillators with exceptional properties, which are tailored for every application [1,[17][18][19]. This is also a prerequisite for medical imaging, where the need for exceptional quality of the diagnostic images as well as the lowest possible radiation exposure of patients as directed by the ALARA principle (as low as reasonably achievable) is a priority [20].…”